[Haskell-cafe] Using Backpack for initial and final encodings

Hi everyone, Ed Kmett recently pointed me towards his usage of Backpack to write some code in the tagless final style, and I've been playing with it and riffing on it for a while. There's a solution to the expression problem in there involving classy Prisms (and now Backpacky Prisms) that seems pretty neat. I've written it up here: https://qfpl.io/posts/backpack-for-initial-and-final-encodings/ Hopefully some of you find it interesting. Cheers, Dave